Introduction

When implemented properly and consistently, strategic pre- and post-workout supplementation can greatly increase the effectiveness of your training. Without optimum nutritional strategies, the body's response to training can only be considered a compromise at best. From this perspective, training and diet cannot be considered as separate factors. The food and supplements that you take, and the work that you faithfully perform in the gym, are both part of your training. On the day of competition it will not be the athlete who trained harder who wins, it will be the athlete who trained smarter.

Exercise causes acute changes in the metabolic environment of muscle tissue. First there is a significant increase in blood flow to working muscles. There is also a sharp increase in catecholamines (e.g. noradrenalin, adrenalin). These changes favor catabolism during exercise, and anabolism immediately after exercise. Because these changes are acute, some lasting only a few hours, the pre and post exercise meals are critical to optimizing the anabolic effect of exercise. This article will discuss pre- and post-exercise nutritional strategies based on current research in this area.

BEFORE
Pre-workout nutritional strategies are based on providing alternative energy substrates (mainly carbohydrate) to preserve energy stores, and taking advantage of increased blood flow to muscle tissue.

Carbohydrates
High intensity exercise places great demand on glycogen stores. Glycogen is the sugar stored in the liver and muscles. Because high intensity exercise burns energy at such a high rate, the body is unable to supply sufficient oxygen to be able to use fat for fuel. Instead, it must use sugar both stored in the muscle and brought in from the blood.

Consuming simple sugars right before training can reduce the amount of glycogen used during exercise. This can prolong performance. More importantly, higher blood sugar and insulin levels appear to create a hormonal milieu favorable to anabolism (growth).

During exercise, cortisol accelerates lipolysis, ketogenesis, and proteolysis (protein breakdown). This happens in order to provide additional fuel substrates for continued exercise. The effects of cortisol may also be necessary to provide an amino acid pool from which the muscle can rebuild new contractile proteins if there are insufficient amino acids delivered from the blood. This ensures that some degree of adaptation can occur regardless of the availability of dietary protein. Over time however, if this process is not balanced with additional dietary protein, the net effect will be only maintenance or even a decrease in functional muscle tissue, as is evident during periods of starvation or prolonged dieting. Fortunately, there is only a non-significant rise in cortisol levels when carbohydrates were consumed during exercise. (Tarpenning, 1998) The net effect is a more rapid increase in the cross sectional area of the muscle fibers with the greatest effect seen in type-II fibers.

This may be a less expensive option for those who were thinking of using phosphatidylserine. In this case, carbohydrate administration appears to down regulate the hypothalamic-pituitary-adrenal axis, probably through insulin or perhaps through the presence of carbohydrate itself. This would, in effect, greatly reduce the body's catabolic response to exercise stress. All good news for bodybuilders.

Protein
Another pre-workout strategy involves taking advantage of increased blood flow to working muscles. Because the availability of amino acids is often the limiting factor for protein synthesis, a pre-workout protein meal will enhance the delivery of amino acids to muscle tissue. Research has demonstrated the effectiveness of a pre-workout protein drink.

Delivery of amino acids has been shown to be significantly greater during the exercise bout when consumed pre-workout than after exercise (Tipton, 2001). There is also a significant difference in amino acid delivery in the 1st hour after exercise, with the pre-exercise protein drink providing a significant advantage. Net amino acid uptake across the muscle is twice as high with a pre-workout protein drink as compared to consuming it after. Phenylalanine disappearance rate, an indicator of muscle protein synthesis from blood amino acids, was significantly higher when amino acids were taken pre-workout. These results indicate that the response of net muscle protein synthesis to consumption of a protein solution immediately before resistance exercise is greater than that when the solution is consumed after exercise, primarily because of an increase in muscle protein synthesis as a result of increased delivery of amino acids to the leg.

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